So I would like to see if I can get some clarification on some terms and this situation in general:
770.133 in regards to non-conductive fiber and power cables:
“Non-conductive optical fiber cables shall be permitted to occupy the same cable tray or raceway with conductors for electric light, power, class 1, non-power limited fire alarm, Type ITC, or medium-power network-powered broadband communications circuits operating at 1000 volts or less.”
So it seems like in general, the NEC doesn't have too big of a problem with non-conductive fiber and power cables rubbing elbows even if not functionally related.
Now on to cabinets and the like:
“Non-conductive optical fiber cables shall not be permitted to occupy the same cabinet, outlet box, panel, or similar enclosure housing the electrical terminations of an electric light, power , Class 1, non-power limited fire alarm, or medium-power network broadband communications circuit.”
Exceptions say that if the power and fiber are functionally related then its OK or if you have a permanent barrier or listed divider its OK.
So basically if the fiber and power are within one of those enclosure like things they can't be together. Lets go one by one for each of the enclosure like things:
Cabinet: From Art 100. Basically a box with a door on a hinge.
Outlet box: Not quite sure what this is. From Art 100 an "outlet" is "a point on the wiring system at which current is taken to supply utilization equipment." Is this synonymous for a junction box?
Panel: Panelboard is made of 1 or multiple panels. Basically a board that has over current devices that is with in a cabinet.
or similar housing the electrical terminations: Terminations is not define. I think a splice is different than a termination. I believe junction boxes often times hold splices and not terminations. A terminal cabinet holds terminations.
If a junction box does not hold terminations then I believe it can be excluded from the list. I am seeing that the list of enclosures above as places where terminal blocks and terminations are made and not splices.
Application related question:
Outdoor installation, want to reuse existing pull boxes/junction boxes (I'm using pull box and junction box with purpose, pull box for the the new installation and junction box for the existing installation, difference is pull box is only used for pulling, junction box used for splices as well). Existing pull boxes have existing power conductors for lighting. New circuits being pulled are fiber and power for a functionally related lighting application.
So the places where the fiber is in the existing junction boxes, it is in compliance with the new functionally related power conductors but as for the existing power conductors it is not functionally related. Is a junction box one of the enclosures that should be disallowed? The existing junction boxes for the existing power circuits make splices to take a feed to lights up and down the existing junction box and conduit installation. If a junction box is one of the places to be disallowed, would placing the fiber in inner duct while in the JB be considered a permanent barrier?
Now more interestingly is that 770.133 is for in building applications, however, there is nothing as in depth for a section that is for outdoor fiber installations! The closest thing I can find is 770.47. Since the NEC is permissive by nature unless strictly prohibiting something (I remember seeing the Code reference for this on the forum before but I can't find it now, can someone help with that?) does that mean that for outdoor installations that don't enter buildings the fiber and power mixing requirements of 770.133 don't apply?
770.133 in regards to non-conductive fiber and power cables:
“Non-conductive optical fiber cables shall be permitted to occupy the same cable tray or raceway with conductors for electric light, power, class 1, non-power limited fire alarm, Type ITC, or medium-power network-powered broadband communications circuits operating at 1000 volts or less.”
So it seems like in general, the NEC doesn't have too big of a problem with non-conductive fiber and power cables rubbing elbows even if not functionally related.
Now on to cabinets and the like:
“Non-conductive optical fiber cables shall not be permitted to occupy the same cabinet, outlet box, panel, or similar enclosure housing the electrical terminations of an electric light, power , Class 1, non-power limited fire alarm, or medium-power network broadband communications circuit.”
Exceptions say that if the power and fiber are functionally related then its OK or if you have a permanent barrier or listed divider its OK.
So basically if the fiber and power are within one of those enclosure like things they can't be together. Lets go one by one for each of the enclosure like things:
Cabinet: From Art 100. Basically a box with a door on a hinge.
Outlet box: Not quite sure what this is. From Art 100 an "outlet" is "a point on the wiring system at which current is taken to supply utilization equipment." Is this synonymous for a junction box?
Panel: Panelboard is made of 1 or multiple panels. Basically a board that has over current devices that is with in a cabinet.
or similar housing the electrical terminations: Terminations is not define. I think a splice is different than a termination. I believe junction boxes often times hold splices and not terminations. A terminal cabinet holds terminations.
If a junction box does not hold terminations then I believe it can be excluded from the list. I am seeing that the list of enclosures above as places where terminal blocks and terminations are made and not splices.
Application related question:
Outdoor installation, want to reuse existing pull boxes/junction boxes (I'm using pull box and junction box with purpose, pull box for the the new installation and junction box for the existing installation, difference is pull box is only used for pulling, junction box used for splices as well). Existing pull boxes have existing power conductors for lighting. New circuits being pulled are fiber and power for a functionally related lighting application.
So the places where the fiber is in the existing junction boxes, it is in compliance with the new functionally related power conductors but as for the existing power conductors it is not functionally related. Is a junction box one of the enclosures that should be disallowed? The existing junction boxes for the existing power circuits make splices to take a feed to lights up and down the existing junction box and conduit installation. If a junction box is one of the places to be disallowed, would placing the fiber in inner duct while in the JB be considered a permanent barrier?
Now more interestingly is that 770.133 is for in building applications, however, there is nothing as in depth for a section that is for outdoor fiber installations! The closest thing I can find is 770.47. Since the NEC is permissive by nature unless strictly prohibiting something (I remember seeing the Code reference for this on the forum before but I can't find it now, can someone help with that?) does that mean that for outdoor installations that don't enter buildings the fiber and power mixing requirements of 770.133 don't apply?
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